• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Forget Commercial Production - It's Patented!

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Slumming around the USPTO's website, looks like someone's got it all covered; US 10218320, Feb 26, 2019 -

Looks like he can use a smaller output transformer, made with cheaper material, by using a little EQ in the signal path to compensate. Seems pretty obvious to me, but hey, I didnt think of it first.

Pretty amusing what they'll issue a patent on these days, as well as the claims in this particular document. (I have to wonder if the examiner had ever seen a tube amplifier schematic from any time in the last 50 years...)

Some of the original text available in this short link US Patent # 1,021,8320. Vacuum tube audio amplifier - Patents.com Enjoy!


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Go to India! Patents are free there...
How much is in US. You may be confusing with copyright. You do not go to patent office and deposit your file . You deal with patent bureau, they prepare all the documents ,drawings the blah blah blahs according to the rules . They will investigate if your idea has not been patented already or in public domain. All this cost lot of money and time . The deposit office will ask you to pay the fee for the first 4 years , afterwards you must pay every year at anniversary ever increasing fee , if you don't , it falls in public domain that same date. . In France in 1985 , the total cost for only national protection costed 4 minimum monthly wages. For International protection , I calculated at that time to end about 1.2 million Francs in 20 years, about 200.000 euros.
To deposit an idea in order to be public domain so that no other is patenting , I was asked 5 years ago on line from European patent authority 520 euros .
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Joined 2015
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It is teoretically possibile to apply for a patent directly to USPTO or with a low cost service provider and pay only a very low fee, if the number of claims is low and the device is very simple. The reality is that you probably will end up with a totally useless patent such as the one ridiculed here. They clearly got a bad advice from some low cost patent firm, skipped the prior art search and arranged a kind of "do it yourself" application. They ultimately got what they paid for. In the software field, when the subject of the invention is basically an idea that anyone can conjure up, examples are plentyful and even more hylarious.
How much does cost to deposit a patent in US .

All my patent applications have been through work, and the company attorneys do the prior art search, and pay the application fees and the maintenance fees. So I'm not sure of the costs.
All I have to do is invent it and give them a general writeup (roughly in journal publication format). They "lawyerize it," let me know when it's filed and when (years later) it's granted.
Disabled Account
Joined 2015
Thank you Magz.
Acoustic Research deposited a patent of Acoustic Suspension. Probably the most stupid invention ever , as it concerns to have the diver in closed box but with softer suspension. It took years for Electrovoice to unvalidate such abusive patent. I do wonder if someone have the reference of this patent.
Here's another doosey; US010216205.

This fellow found experimentally that he can get a signal through (what looks to me) an ordinary vacuum tube circuit topology, but using "zero or near zero" plate voltage. So he successfully patented it in the US. Unsure of the value of this, maybe as deliberate distortion generating elements. The patent teaches that vacuum tube designs intended to run at high voltages can also work at much lower voltages... Apparently, even zero!

So better not lower your B+ too far, else you could have someone on your **** about it! "Hey Buddy! I see you got some of your 12AX7 tubes running at 40V B+. See you in court!" At least until this one gives up on his maintenance costs, after they find no one wants to actually pay up to use the idea.

Seems to be more and more a govt scam to keep people busy documenting and then fighting over nonsense. Unsure which window the "non-obvious" part went out of. Hey! I discovered experimentally that if I put a really small voltage into the speaker coil, it still makes sound! I should try to get a US patent on that...

Apparently, probably could.
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